High-strength hot-rolled steel sheet having excellent local deformability and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-9988697-B2
Application number	US-201214110896-A
Country	US
Kind code	B2
Filing date	Apr 12, 2012
Priority date	Apr 13, 2011
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

This high-strength hot-rolled steel sheet having excellent local deformability contains, in mass %, C: 0.07% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of ⅝ to ⅜ in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 10 μm or less.

First claim

The invention claimed is:

1. A hot-rolled steel sheet comprising:
in mass %,
C: not less than 0.07% nor more than 0.20%;
Si: not less than 0.001% nor more than 2.5%;
Mn: not less than 0.01% nor more than 4.0%;
P: not less than 0.001% nor more than 0.15%;
S: not less than 0.0005% nor more than 0.03%;
Al: not less than 0.001% nor more than 2.0%;
N: not less than 0.0005% nor more than 0.01%;
O: not less than 0.0005% nor more than 0.01%; and
a balance being composed…

Assignees

• Suwa Yoshihiro
• Nakano Kazuaki
• Hayashi Kunio
• Okamoto Riki
• Fujita Nobuhiro
• Sano Kohichi
• Nippon Steel & Sumitomo Metal Corp

Inventors

• Suwa Yoshihiro
• Nakano Kazuaki
• Hayashi Kunio
• Okamoto Riki
• Fujita Nobuhiro
• Sano Kohichi

Classifications

• C21D8/02

  Chemistry & Metallurgy · mapped topic

• C22C38/002

  Chemistry & Metallurgy · mapped topic

• C22C38/04

  Chemistry & Metallurgy · mapped topic

• C22C38/10

  Chemistry & Metallurgy · mapped topic

• C21D8/0426

  Chemistry & Metallurgy · mapped topic